"All of a sudden I found myself inside a very, very huge circle of men who were attacking every inch of my body," she says in a voice that is soft but unflinching.

"They stripped me - their hands were all over my body, violating my intimate parts. I thought I was going to die because they were very aggressive. At a certain point I think I fainted because one of them was trying to strangle me with a scarf that was around my neck."

Several of her attackers followed her all the way into an ambulance, where they carried on assaulting her.

The brutal attack - which lasted more than half an hour - followed a similar pattern to others in the square.

Ms Moheeb was surrounded by a mass of men, several layers deep.

They shouted loudly to passers-by that they were helping her when they were actually molesting her.

'Horrifying'

Sexual violence has long been a problem in Egypt, but mob assaults have increased dramatically since the overthrow of President Hosni Mubarak in 2011.

Media captionHania Moheeb: "Sex attack victim is victimised twice"

The epidemic of sexual violence is the dark side of the revolution.

A recent United Nations study suggested that nine out of 10 Egyptian women had experienced some form of sexual harassment.

UN Women report 2013

Both human rights campaigners and victims like Ms Moheeb say sexual violence is a tool to silence women demonstrators.

"It's not a coincidence that the attacks happen at times of political tension," says Nicholas Piachaud of Amnesty International. "The attacks seem aimed at stopping women coming onto the streets to protest."

'Culture of impunity'

Though she was deeply traumatised by the attack, Ms Moheeb has raised her voice, not lowered it.

She has spoken out publicly about her attack, still a rare move in this conservative country.

Ms Moheeb says the wave of attacks has been fuelled by a culture of impunity.

"Impunity is the number one encouragement for those molesters," she adds. "They can get away with it no matter how extreme they become."

Those who carry out sexual assaults may feel encouraged by ultra conservative clerics like Saad Arafat. The white-bearded cleric maintains that women who complain about harassment are bringing it on themselves.

"I say to the women you are the cause and reason for this," he said in a TV broadcast. "But I say you might have gone out unnecessarily, and therefore Allah set this wolfish devil upon you."

The TV channel which aired him comments now been shut down, but plenty here are ready to blame the victim, as Janet Abdel Aleem discovered at a police station.

The 35-year-old media researcher is a campaigner against sexual violence. She is also a victim.

She was brutally assaulted on two separate occasions in Tahrir Square last November. The second attack was so brutal she had a miscarriage.

I insisted on filing a complaint though the officers were begging me to forgive the attackerJanet Abdel Aleem

Ms Abdel Aleem tried to report the initial attack to the police, but was victimised again.

"When I went into the station I was wearing a badge saying: 'No to Harassment.' The officer's response was that the attacker might have read it without the word 'no', as if I was inviting people to harass me.

"I insisted on filing a complaint though the officers were begging me to forgive the attacker as if he was one of their relatives."

Small wonder perhaps that many victims do not even try to report sexual assaults to the authorities.

The police have now set up a new unit to tackle violence against women.

But victims fear it is a token gesture, with next to no prosecutions taking place. (An appeal court has just reduced the sentence of a man convicted of serial sexual harassment in 2009 from 45 years to five years, according to a local media report.)

Hania Moheeb and Janet Abdel Aleem are among a group of women trying to bring a joint legal case about their assaults.

Asked how long she might wait for justice in Egypt, Ms Moheeb has a quick response: "Decades."

'Harass the Harassers'

Some here are meting out their own form of vigilante justice.

A group called Harass the Harassers patrols the streets during busy holiday periods, on the look-out for attackers. When they find one, they brand him with spray paint.

Image caption
A man has "I am a harasser" spray-painted on his shirt

We set off with some volunteers from the group - young men wearing high-visibility jackets, and carrying tasers. They are filling a vacuum left by the police, according to Mohammed al-Zeiny, one of their leaders.

"There were girls being sexually harassed in the streets," he says.

"No-one did anything to stop this - neither the police not the state, they don't care about this. The idea of seeing a girl being harassed in the street, and doing nothing is not manly."

The powerfully built engineering student is not afraid of using his size. When his group swarmed around an alleged attacker he muscled in - restraining him in a headlock.

The suspect - already being beaten by a bystander - tried to wriggle free.

But Mohammed held firm, while his colleagues spray-painted the man's back.

Guilty or innocent he was publicity humiliated. "I am a harasser" was stencilled across his shirt.